arraysets is package{
  -- test set operations over arrays
  
  A is array of {"alpha"; "beta"; "gamma"};
  
  B is array of {"alpha"; "gamma"; "delta"};
  
  main() do {
    assert A union A=A;
    
    assert B intersect B=B;
    
    assert A complement A = array of {};
    
    assert size(A union B)=4;
    assert size(A intersect B)=2;
    
    assert A complement B=array of {"beta"};
  }
}